Bio

James earned his PhD in Biomedical Engineering from the University of Minnesota. His research was focused on brain computer interfaces using EEG signals. His interests lie in the intersection of machine learning and real-time brain recording. James joined the LBCN with the intent to discover how focal brain activity can be harnessed to decode brain function and how to improve it in conditions such as epilepsy.

Honors & Awards

  • BRIDGE Center Seed Grant, Carnegie Mellon University (2019)
  • T-32 Integrative Training Program in Neuroimaging, The National Institutes of Health (2016)
  • Integrative Graduate Education and Research Traineeship in Systems Neuroengineering, The National Science Foundation (2015)
  • Postbaccalaureate Intramural Research Training Award, The National Institutes of Health (2013)
  • Research with Distinction, The Ohio State University (2013)

Professional Education

  • Bachelor of Science, Ohio State University (2013)
  • Doctor of Philosophy, University of Minnesota Twin Cities (2020)
  • PhD, University of Minnesota, Biomedical Engineering (2020)
  • BSc, The Ohio State University, Neuroscience (2013)

Stanford Advisors

Contact

  • Academic
    jstieger@stanford.edu
    University - Scholar Department: Adult Neurology Position: Postdoctoral Scholar

Additional Info

  • Mail Code: 5235

All Publications

  • Intracranial recordings of the human orbitofrontal cortical activity during self-referential episodic and valenced self-judgments. The Journal of neuroscience : the official journal of the Society for Neuroscience Iravani, B., Kaboodvand, N., Stieger, J. R., Liang, E. Y., Lusk, Z., Fransson, P., Deutsch, G. K., Gotlib, I. H., Parvizi, J. 2024

    Abstract

    We recorded directly from the orbital (oPFC) and ventromedial (vmPFC) subregions of the orbitofrontal cortex (OFC) in 22 (9 female, 13 male) epilepsy patients undergoing intracranial electroencephalography (iEEG) monitoring during an experimental task in which the participants judged the accuracy of self-referential autobiographical statements as well as valenced self-judgments. We found significantly increased high-frequency activity (HFA) in about 13% of oPFC sites (10/18 subjects) and 16% of vmPFC sites (4/12 subjects) during both of these self-referential thought processes, with the HFA power being modulated by the content of self-referential stimuli. The location of these activated sites corresponded with the location of fMRI-identified limbic network. Furthermore, the onset of HFA in the vmPFC was significantly earlier than in the oPFC in all patients with simultaneous recordings in both regions. In 11 patients with available depression scores from comprehensive neuropsychological assessments, we documented diminished HFA activity in the OFC during positive self-judgment trials among individuals with higher depression scores; responses during negative self-judgment trials were not related to the patients' depression scores. Our findings provide new temporal and anatomical information about the mode of engagement in two important subregions of the OFC during autobiographical memory and self-judgment conditions. Our findings from the OFC support the hypothesis that diminished brain activity during positive self-evaluations, rather than heightened activity during negative self-evaluations, plays a key role in the pathophysiology of depression.Significance Statement In direct recordings from the human brain, we observed significant responses characterized by high-frequency activity, aka high gamma, in distinct populations of the orbital (oPFC) and ventromedial (vmPFC) regions of the orbitofrontal cortex (OFC) - corresponding to the location of the resting state limbic network and to a lesser extent default mode network - when human subjects were engaged in self-referential episodic memory retrieval and self-trait judgments. Notably, simultaneous recordings across the two OFC regions in the same individuals revealed earlier activations in vmPFC than oPFC, indicating that the two subregions are involved in different stages of self-referential thought processes. Lastly, in individuals with high depressive symptoms, the OFC responses were significantly reduced during positive self-judgments but not heightened during negative self-evaluations.

    View details for DOI 10.1523/JNEUROSCI.1634-23.2024

    View details for PubMedID 38316564

  • Causal evidence for the processing of bodily self in the anterior precuneus. Neuron Lyu, D., Stieger, J. R., Xin, C., Ma, E., Lusk, Z., Aparicio, M. K., Werbaneth, K., Perry, C. M., Deisseroth, K., Buch, V., Parvizi, J. 2023

    Abstract

    To probe the causal importance of the human posteromedial cortex (PMC) in processing the sense of self, we studied a rare cohort of nine patients with electrodes implanted bilaterally in the precuneus, posterior cingulate, and retrosplenial regions with a combination of neuroimaging, intracranial recordings, and direct cortical stimulations. In all participants, the stimulation of specific sites within the anterior precuneus (aPCu) caused dissociative changes in physical and spatial domains. Using single-pulse electrical stimulations and neuroimaging, we present effective and resting-state connectivity of aPCu hot zone with the rest of the brain and show that they are located outside the boundaries of the default mode network (DMN) but connected reciprocally with it. We propose that the function of this subregion of the PMC is integral to a range of cognitive processes that require the self's physical point of reference, given its location within a spatial environment.

    View details for DOI 10.1016/j.neuron.2023.05.013

    View details for PubMedID 37295420